Conventionally, various ester compounds have been reported as oil bases used for cosmetic materials, etc. For example, JP, A, 2004-256539 (Patent Publication 1) describes a cosmetic composition containing a dispersion having at least one type of liquid fat phase having 1 to 7 carbons and polymer particles dispersed in the fat phase, and at least one type of ester of at least one type of carboxylic acid with a polyhydric alcohol containing at least 4 hydroxyl groups. However, this ester compound is inadequate in terms of properties such as viscosity and spreadability, and is not satisfactory as an oil base used in an external preparation such as a cosmetic material.
As an ester compound used in a cosmetic material, an ester compound obtained by reacting dimer acid and a monohydric or polyhydric alcohol has been examined. For example, JP, A, 2004-256515 (Patent Publication 2) describes an oil base containing an ester in which an oligomer ester of dimer acid with a di- or higher-hydric alcohol is esterified with a monohydric alcohol and/or a monovalent carboxylic acid, or an ester in which an oligomer ester of dimer diol with a di- or higher-valent carboxylic acid is esterified with a monohydric alcohol and/or a monovalent carboxylic acid, and JP, A, 2005-132729 (Patent Publication 3) describes a mixed fatty acid ester obtained by subjecting polyglycerol, dimer acid, and a saturated fatty acid and/or unsaturated fatty acid having 12 to 22 carbons to an esterification reaction. However, these ester compounds are intended to improve gloss, colorant dispersibility, etc. or improve hydration properties, and do not exhibit smooth spreadability, adherence, etc. when applied to skin.
Furthermore, JP, A, 2005-36005 (Patent Publication 4) describes a cosmetic composition containing a cosmetically acceptable medium containing at least one polyester obtained by esterification of an aliphatic hydroxycarboxylic acid ester having at least two hydroxyl groups with a polycarboxylic acid, and at least one hydrocarbon ester other than the polyester. However, this publication gives as a specific example only a polyester of hydrogenated castor oil with dimer dilinoleic acid, and as described in JP, A, 2003-238332 (Patent Publication 5) although such a polyester exhibits effects in terms of an appropriate oily feel, adhesion, emollient properties, etc., it does not give effects in terms of smooth spreadability, a refreshing feel with suppressed stickiness, etc.
On the other hand, JP, A, 2005-179377 (Patent Publication 6) has proposed a hydroxy compound obtained by subjecting diglycerol, isostearic acid, and dimer acid to a condensation reaction. However, although this hydroxy compound exhibits excellent effects in an emulsion, a liquid, etc., the properties required for use in a solid such as appropriate viscosity, slip properties, spreadability, etc. are not sufficient. Furthermore, JP, A, 11-128713 (Patent Publication 7) describes an esterification product of a glycerol polymer, one type or a mixture of two or more types of 12-hydroxystearic acid and/or ricinoleic acid and an intermolecular oligoesterification product of these fatty acids, and an aliphatic saturated dibasic acid having 9 to 20 carbons. However, this esterification product is intended for an emulsion stabilizer, and there is no description of its properties as an external preparation such as a cosmetic material.    [Patent Publication 1] JP, A, 2004-256539    [Patent Publication 2] JP, A, 2004-256515    [Patent Publication 3] JP, A, 2005-132729    [Patent Publication 4] JP, A, 2005-36005    [Patent Publication 5] JP, A, 2003-238332    [Patent Publication 6] JP, A, 2005-179377    [Patent Publication 7] JP, A, 11-128713